Question

What is the role of $ZnC{{l}_{2}}$ in a dry cell.

Answer 1

We know that the dry cell is basically of two types; primary and secondary. A primary dry cell is the one in which the electrochemical reactions consume all the chemical reagents, thus fail to produce electricity and so are neither reusable nor rechargeable.

Complete answer:
As we know that the dry cell is basically a type of an electrochemical cell or a battery which is mostly used for the house equipment and portable electronic devices. The electrolytes present in it are in the form of a paste to form low moisture immobilized electrolytes, which restricts it from flowing and the moisture is low but enough to allow the current to flow. This also makes it easy to transport. An example of a dry cell is a Zinc-Carbon cell. It is a type of primary cell and also known as a LaChance cell. It can produce a maximum of $1.5V$ of voltage. It consists of a Zinc container which acts as the anode negative electrode and a carbon graphite rod which acts as a cathode positive electrode.
Generally, the dry cell consists of the electrolyte which is in the form of paste. The moisture which is present in the paste electrolyte is enough to allow the current to flow between two electrodes. The dry cell comprises zinc anode and carbon cathode. The main purpose of Zinc chloride $\left( ~ZnC{{l}_{2}} \right)$ combines with $N{{H}_{3}},$ released from $N{{H}_{4}}Cl$ present in the cell to form the complex salt $\left[ Zn{{\left( N{{H}_{3}} \right)}_{2}}C{{l}_{2}} \right].$ Otherwise the pressure developed due to release $N{{H}_{3}},$ would crack the seal of the cell. In dry cells the electrolyte does not spill out when we use the dry cell in any orientation. But the wet cell spills the electrolyte out when it has some angle of inclination. This is the main reason that the paste-like electrolyte is used in the dry cell. Most commonly the dry cell battery is the zinc carbon battery.

Note:
Remember that the secondary dry cell has the ability to regenerate the chemical reactions and hence can be recharged with the help of battery chargers. For example: Nickel metal hydride cell, nickel-cadmium cell, lithium-ion cell, etc.